In the recent trend of downsizing electronic apparatuses and demanding for high functionality of electronic apparatuses, there have been advances in a reduction in the size of connection terminals in constituent components (for example, electronic components in liquid crystal products). Thus, in the field of electronics packaging, film-like adhesives are widely used as conductive adhesives that are capable of easily establishing connections between such terminals. For example, the conductive adhesives are used to provide a connection between a printed circuit board such as a flexible printed circuit board (FPC) or a rigid printed circuit board (PWB or PCB) provided with connection electrodes composed of copper electrodes and a circuit board such as a glass board provided with connection electrodes composed of copper electrodes, or to provide a connection between a printed circuit board and an electronic component such as an IC chip.
The conductive adhesives are adhesives having anisotropic conductivity and obtained by orienting and dispersing conductive particles in an insulating resin composition. Each of the conductive adhesives is sandwiched between members to be connected with each other, and heated and pressurized. Through the application of heat and pressure, a resin in the adhesive is fluidized to seal the surfaces of electrodes. At the same time, part of the conductive particles becomes stuck between the electrodes facing each other, and the electrodes are bonded to each other while the electrical connection is established. Conventionally, the surface of a connection electrode formed on a printed circuit board or the like is plated with gold in order to prevent oxidation and ensure conductivity.